To date, 28 species of bats have been confirmed in Poland, the most recent documented species being the common bent-wing bat (Miniopterus schreibersii). It was first recorded in the country in 2015 in the underground of the castle in Rożnów (southern Poland), but the publication describing this discovery was not made available until 2021 (Piksa K., Gubała W.J. 2021. First record of Miniopterus schreibersii (Chiroptera: Miniopteridae) in Poland – a possible range expansion? Mammal Research, 66, 211-215). The common bent-wing bat is a medium-sized bat with brown or gray coloring and a characteristic short muzzle and triangular ears.
Common bent-wing bat caught in Rożnów Castle (Piksa and Gubała 2021)
From the perspective of wind farm investments, such reports have practical significance: acoustic surveys should be prepared to detect and correctly identify rare or new species in the national fauna, instead of assigning them to more frequently recorded/common species. This is important for the aforementioned common bent-wing bat, among other things because its echolocation parameters may overlap with those typical for the pipistrelle genus (Pipistrellus), which increases the risk of misidentification.
Echolocation sounds of the soprano pipistrelle (Pipistrellus pygmaeus)
In the case of bat recordings where the echolocation sequence is short and/or the recording is of poor quality, species identification can often be difficult. If social calls are present in the recording, they can be a valuable aid in identification, as these signals are very characteristic of some native species.
Characteristic social sounds of the Nathusius’ pipistrelle (Pipistrellus nathusii)
It is worth noting that the Ambiens team has experience and training in identifying bat species based on their echolocation sounds. In practice, this means working with materials of varying quality, verifying identifications in the context of signal parameters (including frequency range, structure, and length), and paying attention to features that may be decisive in distinguishing between species with similar sounds. Thanks to this approach, surveys for wind farms, both in pre- and post-implementation projects, is carried out with attention to detail and focused on reducing the risk of misidentification.